Using the first-principles calculations, we explore electronic structures of 2H-$M{X}_{2}$ ($M$ $=$ Mo, W; $X$ S, Se, Te). When number layers reduces to a single layer, indirect gap bulk becomes direct with larger and band curvatures are found lead drastic changes effective masses. On other hand, when strain is applied on an masses vary. Especially, tensile energy while compressive enhances them. Furthermore, much stress leads become metallic.

Phototransistors based on multilayer MoS2 crystals are demonstrated with a wider spectral response and higher photoresponsivity than single-layer phototransistors. Multilayer phototransistors further exhibit high room temperature mobilities (>70 cm2V−1s−1), near-ideal subthreshold swings (∼70 mV decade−1), low operating gate biases (<5 V), negligible shifts in the threshold voltages during illumination. Detailed facts of importance to specialist readers published as "Supporting Information"....

We have investigated the electronic structures of single- and double-layered MoS${}_{2}$, composing heterojunction such as graphene, SiO${}_{2}$ MoS${}_{2}$ SiO${}_{2}$, using scanning photoelectron microscopy. Negative shifts both core levels valence bands toward Fermi energy been observed. In connection with first-principles calculations, we confirmed that direct gap single-layer is changed to an indirect by stacking additional layers via van der Waals interlayer interactions.

We have successfully fabricated highly (up to 6%) Mn-doped bulk Ge single crystals. The lattice constant increases linearly with Mn concentration due the larger atomic radius compared Ge, strongly indicating that ions are being incorporated into host lattice. Alloys lower concentrations showed paramagnetism localized magnetic ions. ${\mathrm{Ge}}_{0.94}{\mathrm{Mn}}_{0.06}$ ferromagnetic ordering at \ensuremath{\sim}285 K, as determined from temperature-dependent magnetization and resistance...

We study the magnetic and electronic properties of defects in ${\text{SnO}}_{2}$ using pseudopotential all electron methods. Our calculations show that bulk is nonmagnetic, but it shows magnetism with a moment around $4.00{\ensuremath{\mu}}_{B}$ due to Sn vacancy $({V}_{\text{Sn}})$. The comes mainly from O atoms surrounding ${V}_{\text{Sn}}$ atoms, which couple antiferromagnetically presence ${V}_{\text{Sn}}$. coupling between different vacancies also studied we found these not only...

We report the effective methods to induce weak ferromagnetism in pristine MoS2 persisting up room temperature with improved transport property, which would lead new spintronics devices. The hydrogenation of by heating at 300 °C for 1 h leads easy axis out plane, while irradiation proton a dose × 10(13) P/cm(2) plane. theoretical modeling supports such magnetic axes.

We report on the discovery of a room-temperature ferromagnetic semiconductor in chalcopyrite $({\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}){\mathrm{GeP}}_{2}$ with ${T}_{c}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}312\mathrm{K}$. have also observed that, at temperatures below 47 K, samples for $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.056$ and 0.2 show transition to antiferromagnetic (AFM) state, so that ferromagnetism is well defined be present between 312 K. The...

We provide a new insight that the sulphur-depleted MoS2 surface can store hydrogen gas at room temperature. Our findings reveal sulphur-vacancy defects preferentially serve as active sites for both chemisorption and physisorption. Unexpectedly sulphur vacancy instantly dissociates H2 molecules strongly binds split exposed Mo atoms. Thereon additional molecule is adsorbed with enabling more physisorption on top around vacancy. Furthermore, increase of further activates dissociative than

Significant enhancement of the magnetocrystalline anisotropy (MCA) an Fe(001) surface capped by 4$d$ and 5$d$ transition metal monolayers is presented in this study using first principles density functional calculations. In particular, extremely large perpendicular MCA $+$10 meV/Ir was found Ir-capped Fe(001), which originates not from Fe but spin-orbit coupling Ir atoms. From spin-channel decomposition matrix electronic structure analyses, we find that strong 3$d$--5$d$ band hybridization...

The electronic band structure of MoS${}_{2}$ single crystals has been investigated using angle-resolved photoelectron spectroscopy and first-principles calculations. orbital symmetry $k$ dispersion these states responsible for the direct indirect gaps have unambiguously determined. By experimentally probing an increase gap, we conclude that a (0002) surface localized state exists just below valence maximum at $\ensuremath{\Gamma}$ point. This originates from sulfur planes within topmost...

Abstract 1 T phase incorporation into 2H-MoS 2 via an optimal electron irradiation leads to induce a weak ferromagnetic state at room temperature, together with the improved transport property. In addition 1T-like defects, on cleaved MoS surface forms concentric circle-type defects that are caused by H/1 transition and vacancies of nearby S atoms Mo atoms. The irradiation-reduced bandgap is promising in vanishing Schottky barrier attaining spintronics device. simple method control improve...

The structural, electronic, and magnetic properties of Fe transition-metal atoms as an overlayer on a nonmagnetic transition metal, W(110), the effects Ag covering magnetism Fe/W(110), are determined by means highly precise self-consistent all-electron full-potential linearized-augmented-plane-wave method based local-spin-density approximation. interlayer spacings Fe-W Ag-Fe from total-energy calculations. We find that relaxed downward (compared to average Fe-Fe W-W bulk bond lengths) 9.5%...

Strain effect on thermoelectricity of orthorhombic SnSe is studied using density function theory. The Seebeck coefficients are obtained by solving Boltzmann Transport equation (BTE) with interpolated band energies. As expected from the crystal structure, calculated highly anisotropic, and agree well experiment. Changes in presented, when strain applied along b c direction strength -3% to +3%, where influence gaps dispersions significant. Moreover, for compressive strains, sign change at...

Magnetism of FeRh (001) films strongly depends on film thickness and surface terminations. While magnetic ground state bulk is G-type antiferromagnetism, the Rh-terminated exhibit ferromagnetism with strong perpendicular MCA whose energy +2.1 meV/$\Box$ two orders magnitude greater than 3$d$ metals, where $\Box$ area two-dimensional unit cell. Goodenough-Kanamori-Anderson rule superexchange interaction crucial in determining phases thin films, are results interplay competition between three...

Effects of charge ordering in the octahedral sites Fe3O4 and CoFe2O4 on their magnetostrictions are investigated using density functional theory plus U approach. Precise description was found to be crucial determining only band-gaps CoFe2O4, but not other physical properties such as lattice constant, magnetic moment, magnetostriction. And Co configuration is important its magnetostriction; most stable results substantially enhanced magnetostriction (−245 ppm), compared that (−25 ppm) Fe3O4,...

We have fabricated Cr-doped bulk Ge single crystal using the vertical gradient solidification method. The material shows ferromagnetic ordering at 126 K, as determined from temperature-dependent magnetization and resistance measurements. A sample with x=0.01 was p type nh=3×1017 cm−3 350 K. measured magnetic moment per Cr 0.83μB 5

We performed the first-principles density-functional calculations to investigate magnetism of palladium films up 21 ML (monolayer) thick, employing highly precise full-potential linearized augmented plane-wave method. The ferromagnetic state is stable in Pd only with particular thicknesses, 1, 4, 9, and 15 ML. While ferromagnetism monolayer due band narrowing, magnetization obviously triggered by quantum well states, rather than surface termination. predicted sizable x-ray magnetic circular...

By using high resolution x-ray photoelectron spectroscopy, we show that inelastic scattering of at low temperature (30–50 K) generates two kinds oxygen species on Pt (111) surface. Intense synchrotron radiation source dissociates molecules into chemisorbed atomic and induces the formation PtO Estimated coverage dissociated is 0.5 ML, suggesting possible p(2×1) surface structure, while shows saturation ML. Molecular dosed 30 K undergoes thermally activated transition from physisorbed to state...

By using higher acceleration energies than the displacement energy of Mo atoms, electron irradiation on layered MoS2 single crystals is found to be an effective and simple method induce diamagnetic ferromagnetic phase transition persisting up room temperature. The easy axis can controllable by regulating dose energy. states are largely attributed strain around vacancies.

Permanent-magnet applications such as electric motors demand a high energy product (simultaneously saturation magnetization and uniaxial magnetic anisotropy) Curie temperature, preferably in $3d$ metals without any rare-earth elements. The authors' first-principles calculations highlight promising pathway to achieving these properties $B2$-ordered FeCo alloy, by interstitial doping with $2p$-electron nonmetal elements, N. This prediction could have real impact on the manufacturing of...